Automatic nut wrench



J. v. LARSON ET AL AUTOMATIC NUT WRENCH Original Filed August 30, 1924 7 Oct. 12 1926. I 1,602,620

J/zrz, Vzarson 3y JOHN v. mason AUTOMATIC NUT WRENCH.

AND AUGUST KURING, OF CHICAGO, ILLINOIS; SAID KURING ASSIGNOR TO SAID JOHN V. LARSON.

PATENT OFFICE.

- Application filed August 30, 1924, Serial No. 735,215. Renewed March 18, 1926.

This invention relates to that type of nut Wrenches in which the operating handle of the wrench is pivotally connected to the stationary wrench jaw and provided with a guideway for the sliding companion movable wrench aw, with said movable jaw forcibly held to an engagement with a nut by a gearing of similar connection between said movable jaw and the pivoted handle, with said movable jaw having a tendency under the influence of aspring to move towards the companion stationary wrench jaw.

The object of the present improvement is to provide a structural formation and arrangement of parts whereby'the interposed spring, such as above referred to, is securely housed within the body of the wrench and effectively protected from accidental injury.

Another object is to provide a movable abutment on the handle member of the wrench for the. aforesaid spring, whereby the tension of the spring can be readily released from its active jaw closing tendency and placed in an inactlve position, whereby the movable jaw member of the wrench is left free for manual adjustment by the fingers of the user, all as will hereinafter more fully appear.

In the accompanying drawing Fig. 1 is a side elevation of a nutwrench having the present improvement applied.

Fig. 2 is a sectional view on .line '2-2, Fig. 3.

Fig. 3 is a longitudinal section on line a 3-3, Fig. 2.

Fig.4c 1s a perspective view of the spring and associated wrench. parts in a separated condition.

Like reference numerals indicate like parts in the several views.

The type of wrench structure shown in the drawing as [illustrating the application of the present improvement, is substantially the same as set forth in our prior applicatlon for patent, Serial No. 669,049, filed Oct. 17

"The relatively stationary body portion 1 ofthe wrench is formed with the usual out standing nut engaging jaw 2 at one end, and

with a pair of oppositely extendin cheekplates 3 inseparated relationto eac other to provide a receiving cavit in which the operating handle 4 is journa led by a pivot pin 5 as shown. The cheek plates,3 in conncction with the usual longitudinal channel in the .body portion 1, provides a slideway for therectilinear movement of the movable wrench jaw 6 to and from the stationary aw 2 aforesaid. In-t-he construction shown said aw 6 constitutes an outstandin portion of a head or block 7 moving in the aforesaid slidewav, and having its back formed with a toothed rack or gear 8.

'of. the hub, with each of such distances slightly less than the "distances across the,

side faces of each respective nut of the range of nut sizes the wrench is designed-to ma nlpulate, and in connection with such progressive increase in the radial pitch lines of the plurality of teeth 10, the formation of such teeth of correspondingly increased sizes so as to provide the requisite strength to resist the increased stress to which they are exposed by the increased size of the nuts the are required to manipulate.

he series of gear teeth 11 of the rack bar 8 of themovable jaw member, have a complementary formation ,to that of the lurality of gear teeth 9 of the wrench han e4, both in relation to pitch lines and increased sizes of teeth, as shown.

The movable wrench jaw 6 in the present type of wrenches, has a yielding tendency towards the stationary wrench jaw 2 bymeans of a spring connection intermediate of the two jaws, with the spring connection acting to maintain the wrench jaw .in a normally closed condition, aswell as to return the jaws to contact with the sides of the nut operated on, whenthe wrench is operated for speed with an opening movement of the jaws in the reverse/stroke or turn of the operating handle. 4. And in this connection the material'part of the present improvement involves a structural formation of a spring of the ty e above described and the associated wrenc arts as follows.

In'one of the c eek plates 3 above described, anannular containing cavity 12 is formed in concentric relation to the pivot pin 5, and separated from the receivlng 01 '1- fice of said pin by an annular wall 13 as shown. 1

Within the cavity 12 is arranged a coiled spring 14 of the scroll type shown, the inner end of which has a lateral prong or extension 15 for engagement in a holding orifice formed therefor in the bottom of said cavity. Theouter end of the spring 14 is formed with a laterahextension or hook 16 having fixed attachment to the adjustable abutment plate or arm now to be described.

The abutment plate or arm has a main portion 17 of a centrally orifice'd disk form with a notch gr recess" 20, for the purpose hereinafter set forth.

In adjacent relation to the outer end of the arm 18 a transverse orifice is formed in the wrench handle 4 and in said orifice is- -arranged a sliding stop pin 21, headed at both ends and capable of limited transverse movement in said orifice. As so arranged,

v and with a headed end of the stop pin 21 pushed into the path of the arm 18, the same is adopted to have holding engagement with the notch 20 with the head of said stop-pin. As so engaged, the tensional stress of the spring 14: acts intermediate of the wrench handle 4 and wrench body 1, to yieldingly force the jaw members together. With a disengagejment between the arm 18 and the stop pin 21, said arm moves against the edge of the cheek plate 3, to a dormant condition, leaving the wrench jaws Free to be moved to and from each other by the fingers of. the user. Having thus fully described our invention, what we claim and desire to secure 'by Letters Patent is 1. In a wrench of the type described, a pair of jaw members, one movable to and from the other, an operating handle pivoted to one jaw member and operatively connected to the otherjaw member, a' spring encircling the pivot axis of the handle memher with one end fixedly engaging the 'aw member to which said handle is pivoted, a

- swinging arm associated with said pivot axis and havmg fixed en agement with the other end of the aforesai spring, and a movable stop member adapted for engagement with stop pin, through an engagement of the said arm to hold the spring in active operation.

' 2. In a wrench of the type described, a pair of jaw members, one movable to and from the other, an operating handle pivoted to one jaw member and operatively" connected to the other jaw member, a spring encircling the pivot axis of the handle member with one end fixedly engaging nected to the other jaw member, a springencircling the pivot axis of the handle member with one end fixedly engaging the jaw meniher to which said handle is pivoted, the jaw member having an annular containing cavity for said' spring, a swinging arm associated with said pivotaxis and having fixed engagement with the other end of said spring, said arm having a circular hub portion forming a closure for the cavity aforesaid, and a movable stop member adapted for engagement with said arm to holdthe spring in active operation.

4. In a wrench of the type described, a pair of jaw members, one movable to and from the other, an operating handle pivoted to one jaw member and operatively connected to the other jaw member, a sprlng'encircling the pivot axis of the handle member with one end .fixedly engaging the jaw member to which said handle is pivoted, the jaw member having an annular containing cavity for said spring, a swinging arm associated with said pivot axis and having fixed engagement with the other end of said spring, said arm having a circular hub portion forming a closure for the aforesaid cavity and with a flange on its free-end formed with a holding notch, and a headed stop pin having limitedlateral sliding movement in the wrench handle and into and out of the path ofsaid swinging arm.

Signed at Chicago, Illinois, this 27th day of August, 1924.

Joan v. LARSON. AUGUST KURING.

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